Yes, if I could only have one or the other, I would choose a fan. Having heatsink and a fan even better.
In my case, the VIM2 sets atop a centrifugal blower( no heatsink). It draws air from the VIM2’s bottom vents. While not ideal, usually don’t see temps move over 60c under any load, and that is with fairly high room temperature.
I intend to mount heatsink and fan at some point, but until then, my crude setup will do.
Some use cheap USB laptop coolers to move the air.
BTW If you are running Android, have a look at the ROMs from @superceleron. To avoid surprises, please carefully read his post before flashing.